The standard Jerry can mount used on Army vehicles was a tray affair with a higher back that bolted on the vehicle, and had a strap over the top and thru the carry handle of the Jerry can to hold it in place. Those are available, but you need either a vertical flat surface to bolt the bracket onto the truck or a horizontal flat surface (running board?) with enough room for the can to fit.
Here are some samples: The 5th one from the top is the old GI style.
http://www.4wd.com/Jeep-Exterior-Pa...ets.aspx?t_c=3&t_s=188&t_pt=8401


Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.